Footpaths in Carmarthenshire: What's the point?

Late in June I spent nearly a week near Carmarthen. I thought I'd get to know some footpaths local to where I was staying.

The Church which turned into a Gurdwara: pre-pub mapping

This is a very belated write-up of the May Nottingham pub meet-up.

First of all it was great to meet will_p, our most productive local mapper, and to welcome Paul the Archivist who has mapped actively in his home town Derby, Birmingham and Cardiff. A few of us met at the pub for an hour walk and a bit of light mapping: this is always a good opportunity to compare notes about how different people map and talk about specific issues as they arise (such as how does one represent the surface of the road below: we didn't have a good answer!).

I find it difficult to think of an area comparable to that around the Lincolnshire Poacher which has a similar variety of different sorts of places within a couple of hundred metres: modern social housing, schools, a university campus, retail and commercial areas, pre 20th century housing, large houses, parks, gardens etc. It's also not that well-mapped, something which only really becomes apparent by walking through and checking OSM with what's on the ground. In fact our little mapping walk showed, once again, how much can be missed when one only uses aerial imagery.

We again chased down a few missing road names, but failed to see any signs on one road. Marcus pointed out a few streets along Woodthorpe Road which were blocked and not mapped properly (these are tree-lined so guessing that they connected from aerial imagery was wrong).

This time we headed into the S edge of Mapperley Park, one of the wealthier parts of the city, and a great contrast from St Anns, just the other side of the ridge line. We only followed three or four roads but it was very clear that the original sources of OSM data were pretty poor: this was a mix of NPE maps and aerial imagery. Density of mature trees in Mapperley Park made it difficult to identify the actual road lines from aerial imagery. We walked down Redcliffe Road the upper parts deeply cut into the rock and supported by Bulwell Stone walls . These stone walls area a classic sign locally of a private development between about 1880 and 1960. After 1960 the quarries were running short of this attractive Magnesian Limestone. Many are now used for housing or industry close to Bulwell town centre.

The most interesting site along this road were a couple of cast-iron boundary markers from 1859: these list the mayor and town clerk of the Town of Nottingham (it didn't become a city until some time later). In style they are very similar to the markers used when the City boundaries were extended in the 1930s (see an earlier post). I was intrigued because I didn't know which area was on the other side of the boundary. Fortunately we have an old map at home (Salmon's map) which is virtually contemporaneous with these boundary markers. I took a couple of pictures of the same area that we walked through showing the state of Nottingham in the early 1860s. This clearly shows the boundary, and that Mapperley Park and much of the Forest were in the parish of Basford. Basford was incorporated into Nottingham in the 1880s.

Also of interest is that the road was then called Red Hill Lane. Some road names in St Anns have been preserved although in altered form after re-development, but quite a few on the roads around Bellevue Reservoir seem to have been lost. It's not clear what name the paths round the reservoir have themselves: this old map calls it St. Anns Hill, which now belongs to a road which was then called Blenheim Villas, whereas modern maps (and some from the 1930s) name it as part of Corporation Oaks.



Returning to the pub along Mansfield Road we had a better look at the prominent church shown at the top of the blog. Paul had noted that it seemed to be a Gurdwara, a Sikh Temple, and as we passed it took a 'photo of the notice board. The following day I felt compelled to do a bit of research: How long had it been a Gurdwara? Who built it? what was it's recent history? I was relieved to discover that it had recently been acquired from the Christian Scientists who have moved their place of worship into their fine office building next door. But originally it was built as a Presbyterian church. So it had been a church when first mapped on OSM, but another object lesson that things ain't what they seem and the importance of ground surveys.

We ended up in the snug at the Poacher for a pie (Paul) and several pints.

Hyperlocal Naming

Stanage Edge, Derbyshire
The site of hundreds of hyperlocal names used by rock climbers.
Photo courtesy of Earthwatcher BY-NC-ND

We had an interesting a discussion in March on the OpenStreetMap talk-gb mailing list arising out of some controversial naming practices in Loch Lomond and Trossachs National Park ("Giro Bay"). Someone suggested that no-one would or should ever add newly minted names on OSM.

This is an extended version of why I think that names widely recognised in specialist communities should be used when appropriate. I call these names "hyperlocal", because many of them are used for naming features or localities which non-members of the relevant community would not recognise, or would see no need for naming them.

Naturalists. This whole post started because someone expressed surprise that 'non-official' names might be entered in OpenStreetMap (all my examples are from Attenborough Nature Reserve, Nottinghamshire). Naturalists, and particularly those managing and using nature reserves, are creating new names all the time. In part this is because often these places themselves are new (for instance old industrial workings and quarries — "The Delta", "The Bund"), but mainly because much greater precision is required for location information. This is really important if one wants to find the only example of a rare plant, or check on a bird-box location, or photograph a rare fungus, or make sure the right tree gets chopped down. Also one becomes increasingly aware of minor differences which dramatically affect the range of plants and animals over a small area. In principle this could be communicated by using grid references and at a fine scale a GPS. In practice names are more memorable, help to delineate areas which grids don't, and are much easier to communicate. Some names stick, others may be concocted but never enter common usage. Some places have multiple names, and it takes a long time to find a consensus ("Old Car Park", "Fishermans Car Park", "Education Meadow", "Corbett's Meadow"). Many names have multiple intelligible variants ("Butterflies", "Butterfly Triangle", "Butterfly Patch"). In other cases it's possible to see how a name changes. For several years charcoal has been made at Attenborough: the area by the kiln is now nearly always referred to as "by the Kiln", whereas it used to be called "Redwings". In other places locations are known by number alone, for instance 'compartment 73'. I have a map of compartment numbers for Clumber Park, but it's an internal National Trust document, they are used in the national Fungal Records database though.

I have added several of these 'made-up' names which are in common usage around Attenborough Nature Reserve: the Delta, Warbler Dell, Dirty Island Bank, Butterfly Patch (in use since the 1960's), Corbett's Meadow (a recent 'official' coinage, in memory of Keith Corbett who was reserve manager for over 30 years until his death in 2007), which is also known locally as "The Fisherman's Car Park", and "The Old Car Park", and Education Wood (a recent unofficial coinage, around 2005). As all the water bodies were created by gravel working, their names have evolved recently too. I have only added those which are in widespread usage: there are perhaps 50-odd names which were coined in the '60s and '70s, mostly eponymic toponyms, but many never caught on.

Carsington Reservoir is another location where local birders have evolved a significant number of toponyms. Any of the Helm "Where to Watch Birds" regional guides will provide many more examples.

Climbers. Hill and mountain areas are chock full of named features which might never be noticed. This isn't surprising, the cliff shown at the top of this post Stanage Edge has 100s of climbs along its length. The convention is that the first people to successfully climb a route have naming rights, but it's more complicated than that. An even smaller crag further S in Derbyshire, Birchen Edge, has a convention that climbs names should have a nautical allusion (Trafalgar Wall, Camperdown Crawl). I would think in Derbyshire alone there are probably well over 5000 named climbing routes. Many of these will be less than 20 m ascent. On the harder ones each hold will be memorable (I'm not yet aware of these being named yet). On the other hand some places fall into disuse. My father and his friends used to climb at Laddow Rocks because it was accessible by bus from the Manchester area. Much of Laddow is now mossy and green, but everything on it still has a name: several guidebooks were published.

Oddly, in bigger mountains such as the Alps there is not this degree of minutiae in naming: or if it exists it's not published so widely. A number of factors influence this. Climbing in the Alps tends to follow obvious lines because there are a lot more of them, and they're much longer. Sport climbing has used pictorial 'topos' for a long time, so they avoid the same need for names as a narrative descriptive system. There are still plenty of these names though, the Eiger Nordwand has lots, all used in many mountaineering books, and giving a title to one: Hinterstossier Traverse, The White Spider, the Third Ice Field, Traverse of the Gods, Exit Cracks and so on. That is just one face of one mountain, albeit a famous one, and there's enough variety in the type of names to give a feel for how they were created.

Skiers are another group who go into the mountains for recreation. In many ski resorts many of the names are invented and often follow a stereotyped pattern typically with lots of alpine fauna: White Hares, Pika, Marmots, Chamois, Ibex, Ptarmigan. The older European resorts still use lots of names which arose naturally from older uses.

St Anton in the Tirol has many ski runs and locations named after alpine meadows. Some of these, such as Gampen (often Gampli) have an interesting linguistic history indicating the presence of speakers of a latin-derived language in the area similar to modern Romansch. Mattun, is another name ultimately derived from latin, referring to a characterstic member of the mountain vegetation. Both of these are fairly common place name elements close by in the Eastern Graubünden. (Place name etymology from the Swiss Alpine Club guides). In addition to the regular runs, St. Anton has a host of well-known, named, off-piste runs. The photo shows the top of a broad but steep gully off the Schindlerspitze: but, I never learnt the names of these gullies. Some of the seriously steep chutes have names which are closely guarded secrets passed on only to those who have skiied them.

Les Grands Montets, Argentiére from La Flégère

Photo courtesy of rickardengstrom CC BY-NC-SA

On the Grands Montets many apparently non-obvious features have names (often different names in different languages): Combe des Amethystes or the Italian Bowl; Canadian Bowl. Again these are not to be found on maps, but are widely used by people who know the area. One or two specialised publications use them too. It's possible to ski a line a few metres from the Italian Bowl and not be aware that its there: even then finding the direct entry which gives an exhilarating steep start requires precise knowledge of the local geography. So once again, these names have arisen from a need for much greater precision than might otherwise be expected.

Ski racing requires a heightened awareness of terrain which again tends to drive increasing precision in naming. One of the oldest open downhill races in the Alps is the Parsenn Derby. When I first visited Davos the piste which formed the lower part of the course had markers giving the names of each turn and schuss. nowadays the course is shorter still, but still features places like the 'S-bends' and the 'Derby Schuss'. It's not for wimps like me:




Motor Racing. Any one who has followed a Grand Prix will know that every part of the track has a name. Of course on a modern track these names will have been invented and assigned by marketeers, but on courses with a long history, like Silverstone, it's easy to guess how the names came about. Early users probably said things like 'I came off at the corner near Stowe', which being cumbersome would get rapidly shortened to Stowe Corner. Of course names were useful to everyone: drivers, instructors, marshals, commentators and spectators. Now they integral to what people expect of a motor racing track. Many of these are captured on OSM, including the circuit featured on Top Gear.


Fishing. I know little about fishing, but it struck me that fishermen must have names for favourite spots, and then I came across the wonderful annotations of Walking Papers by Kirk Lombard. The one I show above is near Fishermans Wharf, San Francisco, with one fisherman's name "Striped Perch Hole". Incidentally, this seems to be a great example of using Walking Papers (and OSM) in an innovative and unexpected way.

Names seem to evolve in each of this situations in similar ways. Often they are created by pragmatic shortening of a description. Memorable events, and the people associated with them, are another rich source of names. Things also get named after people as a token of appreciation, respect or a with to remember them. Thematic naming sometimes works, but often ends up being insufferably twee, and is often resisted or subverted, particularly by wit.

One last one example are local names to the swimming holes on Fairham Brook by Keyworth Meadow NR: see Neil Pinder's article on the parish website. I've asked around for other examples, and someone with extensive experience of forestry noted that workers named landscape features in a very similar way to naturalists I'd be very interested to hear of other examples, particularly outside the interest domains I've covered in this post.

The ability to map these hyper-local toponyms is a very attractive part of OSM. Of course, they need to be researched accurately to ensure they are names which are used rather than 'book-names'.

POSSUMs

Check the tongue!
courtesy of wollombi CC-BY

Not cute animals or vicious pests, but Persistent Open Streetmap Unique MapIds!

I've been intrigued by the idea of creating persistent IDs for geographical objects in OSM for a while. Although things in OSM do get a unique ID there is absolutely no guarantee that a given object will retain a single ID, or that a given ID will not be used for multiple objects over time. A classic example is the pub initially mapped as a node, then with a building outline traces, and finally the tags are moved from the node to the building and the node deleted.

Persistent IDs would make it much easier to link external data sources to OSM data. It may obviate the need to add certain types of data directly to OSM. SteveC pointed out the problem of business names in a comment on another post here.

The basic problem is conceptually not too difficult: I've done similar things with bank customer and account data. In a typical business application the problem is, however, that although individual systems usually have persistent IDs there is no single one which links across systems (imagine say multiple bank accounts, a credit card and an insurance policy). With OSM we don't even have this luxury.

My basic notion would be to choose something like the minimum node ID of an object when it is first created and use that as a reference throughout its OSM life-cycle (including, potentially, several deletion and restoration events). Some kind of collision avoidance is needed for objects which share nodes, and handling of certain border cases of ways sharing all their nodes and some types of relations).

Each time an object is touched in a changeset a process is needed to determine what happens to its persistent ID. In most cases nothing will have affected it, but it may be difficult to ensure that these cases are identified. In general geometry changes are unlikely to have an impact whereas changes in topology will: but, I don't know what one should do in the case of inaccurately mapped objects which change position significantly. Changes in topology may result in logical merges and splits of objects previously regarded as atomic, so I imagine the relationships between POSSUMs will need to be stored. Consider a road segment (A->B) between two junctions which gets edited and an additional junction is added between the two (A->C->B): two new identifiers need to be created for A->C and C->B which are children of the original A->B.

Here'a s list of other characteristics, in no particular order, which I think they should possess:

• I think POSSUMs should be approached as an enabling technology: there may be many different persistent ID schemes depending on individual use cases. Some people may be interested in the road network, others might be interested in building outlines, or it might be a specific geographical area, and so-on.
• POSSUMs therefore should be independent of the OSM data infrastructure: of course if they proved very useful then OSMF might want to provide them as a service.
• POSSUM creation needs to be rule based: starting rules will be based on tags, and some aspects of geometry (e.g., road junctions).
• They need only cover a subset of data. New subsets should be capable of being added to an existing POSSUM data store (the cage?).
• It should be possible to add history of elements retrospectively and a pre-existing POSSUM to be used to identify the older versions of an element.
• POSSUMs would only be created for tagged objects (excluding things like fixme, note, source etc.)
• POSSUMs and OSM objects would have a many-to-many relationship. Some means of identifying parts of a way (e.g., road segments), and POSSUM roles will be required (e.g., pub as premises or building, pub as business).
• Relationships between POSSUMs may require some manual maintenance.
• Applying changes to rules means they also need to be applied retrospectively, thus some POSSUMs will be superseded (just as in the new junction case). This is probably technically the most complex part of the idea.

The primary use case for POSSUMs is for the maintenance of linkages between external data (e.g., public open data) and OSM objects in a way which minimises the amount of external data which needs to be imported into OSM. This in turn should reduce the maintenance overhead of keeping OSM data in sync with external sources.

POSSUMs might also be useful for OSM mappers when frequent uploads to the planet database are impossible. This commonly occurs in third-world countries, but also in crisis mapping and disasters when telecom resources are unavailable. At the moment mapping in this situation can give rise to large numbers of conflicts which are difficult to resolve. Use of persistent IDs might make the conflict resolution process easier.

Aaron Cope has already done some much more sophisticated thinking for the use case of a worldwide building register. Check out his building=yes site using WOEIDs. I am sure there are others thinking about this: let's get the discussion rolling.

I'm grateful to Bob Chell of 1-spatial for a brief discussion of the basic notion at SotM10, Girona. This encouraged me to believe that the idea was not completely barking mad. But any remaining nuttiness is entirely my own.

On the histories of OpenStreetMap data

Peter Körner (MaZderMind) has the recently made available extracts of selected areas from the OpenStreetMap full planet history. These are of various Länder of Germany, but are big enough to be interesting and small enough for repeated processing and analysis.

Handling the history of OSM edits is interesting in its own right, but it also has an immediate practical importance as some edits will not be carried forward with OSM once the OdBL licence change is completed. Tools to process and analyse the complete edit history are needed as part of this change.

My main interest is to visualise past states of the database conveniently. The image below is of Berlin from 31st March 2009. This image was generated by re-extracting data from the history using osmosis (regular snapshot schema tables were replaced by views on history tables) and re-importing with osm2pg2sql. This process is too involved and slow for rapid visualisation of historical views of the data, but does demonstrate that reasonable results can be achieved without elaborate changes to the snapshot schema.

I'm also interested in the technical aspects of handling OSM history: I have worked on temporal database schemas in the past. Some of these were more complex than OSM, as they stored not just history of the system (transaction time), but history of the real-world (valid time). This is also something which intrigues me: how one might store real-world history in something like OSM. In OSM we don't make any attempt to discover when a pub opened or when it closed, we just know that someone added the pub to the system and that later someone removed it. Although it might seem reasonable to assume that the pub closed between the two events, it might be the original edit was by someone who used the pub 20 years ago, and it closed 19 years ago.

My initial approach is simple, some might say naive. This is to basically take a schema very similar to the current API schema and make minor modifications to it. The main change is to add another timestamp column to the main tables, with the time period between the two timestamps representing the period when the given primitive (node, way, relation) was valid. This is partly a convenience for querying the data, but it also has the advantage that we can work with partial histories if some versions are missing. The main reason for doing this, though, is to use timestamps as an additional part of the compound key for way geometries. This avoids having to generate another system key to add to the identifier and version.

Way geometries are the crucial problem in making historical data convenient to render. A given version of a way may have many geometries, depending on how many of the nodes comprising the way have changed position, and, indeed, how frequently. Each time a node changes the geometry of all its parent ways may change: of course a node might just be touched (updated with no change), or might only have its tags modified. In the first instance I ignored these issues, although about 40% of all node changes in the Berlin data do not affect position.

My first step was to find for each way version all the start timestamps for the nodes belonging to that way version and where the node version validity period overlapped that of the way version. As the way version start and end timestamps must also be considered I did this using a UNION:

SELECT
w.way_id,
w.version,
greatest(n.tstamp_from, w.tstamp_from) AS tstamp_from
FROM way_hist w
JOIN way_node_hist wn
ON w.way_id = wn.way_id
AND w.version = wn.version
JOIN node_hist n
ON wn.node_id = n.node_id
AND w.tstamp_from <= n.tstamp_to
AND w.tstamp_to >= n.tstamp_from
UNION
SELECT w.way_id, w.version, w.tstamp_from
FROM way_hist w

It's easy to add a valid end date column to this data using a SQL windowing function.

This gives us the total number of historical records we will need to store to access all distinct geometries of ways in the data set.

Exactly the same approach can be used to extend the way_nodes table with node version, and a validity date range based both on the way version and the node version. Indeed the range of way geometries can be derived from this data, but because we also need to slice up the validity range of an unchanged node for each way geometry it is convenient both conceptually and practically to keep these data separate.

With this data we can now start to generate all the historical way geometries. Unfortunately this is computationally expensive in PostGIS: one of the reasons Osmosis provides options for doing this before loading into the snapshot schema. I used the aggregate ST_MakeLine postgis function, which requires that the nodes be correctly sorted in the input.

With historic tables for nodes, ways, and way geometries created the next step was to create history tables which mimic the tables created by osm2pgsql for mapnik rendering. For nodes this is relatively simple, its just a big query converting relevant hstore data into columns along the lines of tags->'highway' as highway with the addition of my two timestamp validity columns. For ways it is more complex: the z_order and area columns requires population, and some ways need to be treated as polygons not lines. Thanks to asciiphil I was pointed to the relevant routine in the back-end processing of osm2pgsql which handles z_order. This is simple enough to replicate in SQL. For deciding which ways to add to the lines and polygon tables I used the default.style file from osm2pgsql storing this in a table.

My first pass seemed to work OK: I didn't try and turn linestrings into polygon geometries, and I didn't do anything with relations. This was the result:

Really this is a dismal failure. Firstly running mapnik to generate the image took forever: each query was doing a table scan on the lines table rather than using the GIST index on the geometry. Secondly, it turned out that I had a problem with the generation of geometries in PostGIS: hence the lines all over the place. Node order in ways was not carried over properly into the MakeLinestring function.

Obviously, I'd hoped to get further with this, but I'm going to have to concentrate on getting the geometries right: testing using a correlated query seems to generate sensible results. That being said, small volume queries with aggregation seemed to work properly too. A kludgey solution to mapnik performance would be to just extract data in the map extent bounding box before running the mapnik style, and I may do this before looking at the PostGIS performance issues systematically.

A few other things of potential interest: the Berlin data has around 250k ways, collectively with over 600k versions. I identified around 1.6 million potential geometries for these ways. The actual number of distinct geometries is substantially smaller than this because of the high proportion of node version changes which do not affect position.

No doubt far more sophisticated things will be implemented at the upcoming hack weekend. Personally, from my experience so far, I'd like to see at least some history support in the existing tools.

Access Land

Snowdon has experienced flurry of edits on OpenStreetMap after the last two long weekends. I happen to be one of the culprits as I've been adding some detail from last July: not least because a family member is planning an attempt on the Welsh 3000ers next month.

The availability of Bing aerial imagery allows a lot more detail to be added, particularly when I can relate it to geotagged photos. I've been able to add:

• walls and fences alongside or crossing tracks;
• bits of marshy ground;
• extend paths which I saw, but didn't walk;
• and, correct alignment of streams and rivers.

In doing so I've also noticed quite a few things which I recorded but had not transferred to OSM: notably stiles and gates.

Whilst looking at these photos I noticed one of a stile had a roundel indicating the start of Access Land. I've suggested before that it's worth mapping these locations as the complete area covered by access land is only likely to be worked out through gradual accumulation of access points. However, when push comes to shove, I'd not done it myself and couldn't think of an obvious tag for it.

I also found a photo of a large notice for the area, Glyn Rhonwy. This contains a lot of old slate quarries including one huge hole. The notice states that the upper part of the area is access land. However the stile we went over when we came out of the old quarry area had a rather threatening warning notice. This appears from the Ordnance Survey mapping to be exactly where the Access Land starts.

There was another puzzle on the edge of Llanberis. We wanted to avoid walking straight down the road, so had aimed for a footpath marked on the map leaving at a corner of the road above the tea shop at Penceunant Isaf. Checking the OS map today I see that this is also Access Land. All we found was a firmly locked gate.

All in all the Access Land areas in Snowdownia are not that well marked, and are often huge: making them poor targets for mapping. In most cases they're fairly obvious, or are areas where access has been presumed for many years, so adding them to OSM is not a huge help for the walker. Closer to towns and villages there still seems to be plenty of ambiguity. I'm not a fan of the huge intrusive notices that do exist either. They seem inappropriate in a National Park.

Although I added a lot of detail in Snowdoia, I needed to find somewhere else to look at mapping Access Land.

The one place I have been in the past couple of years which is access land and where I probably have enough information to map access land is Parkhouse Hill. This striking little hill, one of a pair of fossil coral reefs (the other, Chrome Hill is shown above), lies just inside Derbyshire in the upper reaches of the valley of the Dove. It is also one of the places which was pretty inaccessible until Access Land was introduced by the 2000 CRoW act.

I took a whole series of photo from the ridge of the hill in September 2009, but without good aerial imagery it was not possible to delineate the outline of the accessible area. Only when writing this post did it occur to me that I could now complete this mapping. Accordingly, I've mapped the access land itself as a relation, and added the tag entrance=access_land where I recorded the relevant sign. The tagging is still pretty tentative, but I hope having something concrete will lead to a common approach.

Radburn : exemplar or nightmare

Radburn is a small community in New Jersey.

View Larger Map

Until a few weeks ago I'd never heard of it, but at a friends party we got talking about The Meadows area of Nottingham, how it's changed and how it might change again. The council plan to partially revert the area to a gridded layout and reintroduce a linear shopping street. The area as it is now consists of many short cul-de-sacs off orbital distributor roads, with many houses accessed along paths or through communal green space. Radburn, NJ is the archetype for this type of layout.

I have been mapping The Meadows in a desultory way now for a while: it's not the best part of town so I like to keep mapping visits fairly short. The areas which were re-developed in the early 1980's have an amazing complexity of footpaths, and short side roads. Varying height buildings also sometimes contribute to a canyon effect with the GPS, particularly in the parts which still consist of late 19th century terraced housing.

The Meadows were originally the water meadows of the town of Nottingham, famous in the spring and autumn for displays of crocuses (Crocus vernus in Spring and C. nudiflorus in Autumn). These non-native plants are supposed to have been introduced to the Nottingham area by the monks of the Clunaic Lenton Priory. They still survive in various sites in and around the city (for instance the General Cemetery, Waterloo Promenade, University Park). The area started being developed after the Nottingham Enclosure Act of 1845, when certain parts of the area were dedicated as green spaces (e.g., Queen's Walk). The remainder was largely developed as high density terraced housing with some small scale industry. A colliery opened by the River Trent around 1910, followed by a council-owned power station (both now the site of a retail park). This was what led to the story of an ignorant DJ introducing a request with "Crocus Street, The Meadows. What a lovely address!".

By the 1960s this was one of the areas the council was anxious to re-develop in what were then known as slum-clearance programmes. The whole western portion was demolished in the mid-1970s, to be replaced by lower density housing with much more green space and small gardens for most properties. Additionally, private developers also built housing in this area. The remainder was re-developed piece-meal with the larger original houses being kept smaller less salubrious places being replaced. This accorded with changing planning fashions, with 'cellular renewal' replacing big bang clearance projects. Probably this was because by the late '70s it was clear that there were problems with many of the replacement buildings of the 1960s.

What staggers me is that now, thirty years later, the council wants to 'regenerate' the area. Apparently, its problem is all to do with the Radburn layout.

View Larger Map

One of the great things about worldwide on-line maps is that we can look at places as far apart as New Jersey and Nottingham in a similar way. On OpenStreetMap the cartography is the same worldwide too. This really brings home the differences between the real Radburn, and "Radburn", the planners concept.

The Meadows is obviously much more densely populated: it has a highly convoluted network of paths, whereas in the Radburn the purpose of each path is pretty clear just from the map. The green spaces are smaller, and less connected too. However, The Meadows housing is far pleasanter than its predecessors and the green spaces do sustain a decent amount of wildlife.

I also, doubt if Radburn has a deeply obscure house-numbering scheme, with houses on the same road having different streetnames. Some named roads don't have any addresses associated with them at all.

There are plenty of other places in the UK which are tarred with the now tainted "Radburn" name, like Oxmoor, Huntingdon, a suburb of Havant, suburbs of Telford such as Woodside, Dunclug, Ballymena (NI), and Deanbank, Penicuik (Scotland). Many of these bear only a tenuous resemblance to the original: a planning concept having been transmitted by chinese whisper. Some of the problems are glaringly obvious when one tries to map these places: its difficult to determine addresses, there are far too many paths around the back of properties, few shops have survived, the green space is festooned with "NO BALL GAME" notices. BUT, just as these designs were a planning fashion, it looks like denigrating them is one too. It seems too easy to lay the blame for problems in these areas on the original planners and architects, rather than understanding them as aspects of more complex social issues.

In case of The Meadows, the money for its has 'regeneration' disappeared in the great wave of government cuts. Perhaps this will lead to a more incremental approach, rather than the traditional waving of the planners magic wand to fix social problems.